Description: The age of lake scientists determine into 25−35 millions years. This fact also makes Baykal with unique natural object, since the majority of lakes, especially glacial origin, live on the average of 10−15 of thousand years, and they are then filled up with silted sediments and are swamped. The origin of Baykal, until now, causes scientific disputes. There is no doubt that lake is located in grooved cavity and on the structure similarly, for example, with the pond of dead sea. Some researchers explain the formation of Baykal by its arrangement in the zone of transform breaking, others assume the presence near Baykal of mantle [plyuma], the third explain the formation of cavity by passive [riftingom] as a result of the collision of Eurasia and Hindustan. However that may be, the conversion of Baykal continues, until now, - in the environments of lake the earthquakes constantly occur. There are the assumptions about the fact that the sagging of cavity is connected with the formation of vacuum centers as a result of the effusion of basalts to the surface (quaternary period).